In anticipation of the fortieth anniversary of the founding of the American Society of Missiology in 2013, in 2010 ASM President Robert Gallagher requested Wilbert Shenk to prepare a forty-year history of the Society. The experience over the past four decades has demonstrated clearly that if an organization is to serve its members, it must be responsive to its changing environment. The initiatives taken in the third and fourth decades to realign ASM structures and patterns to better serve its members are instructive. Re-reading the official minutes and reports of the ASM Board of Directors, the Members Annual Meetings, and Board of Publications one is reminded that a scholarly society depends on the volunteered labors of many peopleĆ¢editors, board members, planning committees, officers, and others. An effort has been made in the present account to draw attention to at least some of those who have served so faithfully and effectively. As ASM embarks on its fifth decade it does so with renewed energy and hope. The Mission of God calls us to face and move toward the future, not the past. Yet that continuing pilgrimage should always be pursued with keen awareness of the generations of witnesses who have preceded us. This fortieth anniversary account of the American Society of Missiology has built on the two previous editions. But an effort has been made to revise, update, and extend this history, highlighting both failures and achievements.